/*  */
.title-enter {
  opacity: 0;
}
.title-enter-active {
  opacity: 1;
  transition: opacity 2s ease;
}

/* 执行结束：卸载时的动画 */
.title-exit {
  opacity: 1;
}
.title-exit-active {
  opacity: 0;
  transition: opcity 2s ease;
}
